Extended Electrical and Photonic Characterization of GaN-Based Ultra-Violet MicroLEDs With an ITO Emission Window Layer

• Published in: IEEE photonics journal Vol. 12; no. 6; pp. 1 - 9
• Main Authors: Tsai, Yi-Lin, Huang, Sheng-Kai, Huang, Huang-Hsiung, Yang, Shu-Mei, Liang, Kai-Ling, Kuo, Wei-Hung, Fang, Yen-Hsiang, Wu, Chih-I, Wang, Shou-Wei, Shih, Hsiang-Yun, Xu, Zhiyu, Cho, Minkyu, Shen, Shyh-Chiang, Lin, Chien-Chung
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.12.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Arrhenius plot; Current injection; Current-voltage characteristics; Electrical properties; Emission; Gallium nitride; Gallium nitrides; GaN; Leakage current; Leakage currents; Light emitting diodes; low temperature current-voltage characterization; micro LEDs; Quantum efficiency; Temperature dependence; Ultra-violet emission
• ISSN: 1943-0655; 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2020.3037220

We determined the optical and electrical characteristics of GaN-based, ultraviolet micro light emitting diodes (microLEDs). Such microLEDs are essential to next-generation high-resolution micro-displays. Square-shaped microLEDs of different sizes (side lengths: 5-50 μm) were designed. The peak emission wavelength of these devices shifted <0.15 nm during the current injection. The 50 μm device had a 3.8 times greater relative illumination intensity than did the 5 μm device, suggesting a degradation in quantum efficiency in small devices. Measurements of temperature-dependent reverse leakage current indicated (1) thermal activation from deep centers and (2) a high percentage of components with surface recombination current in the small devices.